Jacquard mechanism for knitting machines

Abstract

An electromagnetically controlled jacquard mechanism is comprised of a row of interchangeable magnet-unit modules slid onto a shared mounting rod, each magnet-unit module comprising a permanent magnet, an electromagnetic winding and a pole shoe structure. Associated with each magnet unit is a respective jack displaceable between a first and a second position and urged towards second position by a respective biasing spring. When in first position, each jack engages, at a flat holding surface thereon, a flat holding surface on the pole shoe structure of the respective magnet unit, in flat surface-to-surface contact therewith, to maximize the holding force achieved with a given permanent magnet. When the respective coil is briefly energized the resultant flux opposes that of the associated permanent magnet, and the associated jack is pulled by its biasing spring to second position. To facilitate the aforementioned flat surface-to-surface contact, the pole shoe structure of each magnet unit is discrete from the remainder of the magnet unit and somewhat rotatable about the mounting rod and somewhat shiftable in a respective plane normal to the longitudinal direction of the mounting rod, e.g., so that when a respective jack is moved into engagement with the holding structure the pole shoe structure will assume an adjusted position in which flat surface-to-surfce engagement between it and the respective jack is achieved.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims: 
     
       1. A jacquard mechanism comprising, in combination, a row of jacks and means mounting the jacks for movement between a first position and a second position, a row of magnet units, one for each jack, each magnet unit comprising a permanent magnet, a pole shoe structure, and a coil, the permanent magnet being operative for holding the respective jack in first position against the respective pole shoe structure, the coil when energized with current of a predetermined polarity generating a field opposing the holding force exerted upon the jack by the permanent magnet, a mounting bar, the row of magnet units being all identical and thereby interchangeable and being removably mounted on the mounting bar, biasing means operative for urging the jacks towards the second position thereof, and control means operative for energizing the coils of selected magnet units with current of the predetermined polarity. 
     
     
       2. A jacquard mechanism as defined in claim 1, the magnet units being of generally annular configuration and having central openings surrounding the mounting bar, whereby during assembly of the magnet units on the mounting bar the magnet units can be pushed one by one onto the mounting bar to form the row of magnet units. 
     
     
       3. A jacquard mechanism as defined in claim 2, the mounting bar being of circular cross-section, furthermore including means for holding the magnet units in place on the mounting bar to prevent rotation of the magnet units about the mounting bar. 
     
     
       4. A jacquard mechanism as defined in claim 3, the holding means comprising bars extending along the row of magnet units, the bars being provided with a row of holding portions which engage successive ones of the magnet units of the row of magnet units. 
     
     
       5. A jacquard mechanism as defined in claim 1, the jacks each having an open recess, the mounting means for the jacks including a jack mounting rod extending through the open recesses of the jacks and mounting the jacks for tilting movement between the first and second positions thereof, each jack having a butt for transmitting pattern data to a component of a knitting machine controlled by the jacquard mechanism, each jack furthermore having a holding surface portion of magnetically attractable material which engages the pole shoe structure of a respective magnet unit when the jack is in the first position. 
     
     
       6. A jacquard mechanism as defined in claim 1, the row of jacks, the row of magnet units, the mounting bar and the biasing means being a first row of jacks, a first row of magnet units, a first mounting bar and first biasing means, furthermore including at least one further row of jacks, at least one further row of magnet units, at least one further mounting bar for the further row of magnet units and further biasing means acting on the further row of jacks, the jacks of each row being of a different respective configuration, the magnet units of each row of magnet units being differently offset from each other as considered in the direction in which the mounting bars extend. 
     
     
       7. A jacquard arrangement as defined in claim 1, the coils of the magnet units being connected to the control means by plug and socket connectors. 
     
     
       8. A jacquard mechanism as defined in claim 1, furthermore including adjusting means for adjusting the biasing force provided by the biasing means. 
     
     
       9. A jacquard mechanism as defined in claim 1, furthermore including a travelling component which travels along the needle bed of a knitting machine, the travelling component being provided with a cam operative for successively displacing all jacks which are in the second position to the first position thereof. 
     
     
       10. A jacquard mechanism as defined in claim 1, the pole shoe structure of each magnet unit being flat, each jack being provided with a flat magnetically attractable holding surface portion which is in flat surface-to-surface engagement with the pole shoe structure of the respective magnet unit when the jack is in first position, the pole shoe structures each being mounted displaceably on the mounting bar whereby to facilitate adjustment of the positions of the pole shoe structures such as to assure such flat surface-to-surface engagement. 
     
     
       11. A jacquard mechanism as defined in claim 1, furthermore including a knitting machine having a needle bed, the row of magnet units and the row of jacks extending over the whole length of the needle bed, the jacks being each operative for controlling a respective one of the needles of the needle bed. 
     
     
       12. A jacquard mechanism as defined in claim 1, furthermore including a pattern wheel provided with pattern-wheel jacks, the pattern wheel travelling along the row of jacks of the jacquard mechanism with the pattern-wheel jacks being programmed by the jacks of the jacquard mechanism.